PROJECT SUMMARY Up to a quarter of a million Americans annually suffer from acute respiratory distress syndrome (ARDS), a life- threatening syndrome of acute respiratory failure associated with common conditions such as pneumonia, aspiration, sepsis, severe trauma, and massive transfusion. Mortality of ARDS is estimated to be as high as 40%, and those that survive commonly experience long-term cognitive, emotional, and physical impairments. Many years of research of many different potential therapies for ARDS have led to the discovery of only a few interventions that are actually proven to reduce mortality. One of these therapies is prone-positioning, where patients are rotated with their chests facing down, which confers physiologic benefits from improved gas exchange and reduced lung injury that in turn lead to increased survival. The definitive randomized trial in 2013 demonstrated a reduction in mortality in patients with severe ARDS from 32% to 16%, and a subsequent multi- society clinical practice guideline included prone positioning as one of only two strongly recommended therapies for patients with severe ARDS. Nonetheless, recent observational studies demonstrated that a vast majority of eligible patients, up to 90% in one study, do not receive this life-saving therapy. The barriers and facilitators of prone positioning for patients with ARDS are unknown. This therapy has unique challenges, including that its potential adverse effects (such as facial pressure ulcers and dislodgement of tubes and lines necessary for life support) are potentially more common among inexperienced providers; and that it requires people power ? up to 6-8 staff members ? to safely rotate a patient. Finally, common barriers to evidence- based care for ARDS may also contribute, including lack of knowledge of the evidence and diagnostic challenges of ARDS. Therefore, the main objective for this project is to identify barriers and facilitators of prone positioning. We will apply frameworks of implementation science to conduct and interpret qualitative interviews of multiple stakeholder groups (including attending critical care physicians, ordering providers, respiratory therapists, bedside nurses, and patients and family members) within 8 intensive care units (ICUs) of two hospital systems. We will subsequently convene a stakeholder task force, composed of a small group of interprofessional representatives from the study ICUs, and use an intervention mapping process to develop several candidate implementation strategies for improving utilization of prone positioning. Lastly, we will administer follow-up interviews of the clinician stakeholders regarding the acceptability and feasibility of the candidate implementation strategies. The ultimate goal of this project is to prepare for a future pragmatic trial of simple, readily scalable implementation strategies to improve evidence-based practices among patients with very high morbidity and mortality.